1. Field of the Invention
This invention relates to a gastrointestinal sphincter for surgical implantation to surround and embrace a patient's lumen (e.g. bowel) for articulating the lumen by means of a single, continuous fluid circuit by which variable occlusive pressures can be selectively and controllably generated for achieving coaptive continence.
2. Prior Art
Cancer of the colon typically occurs in the rectosigmoidal area of a patient. Halting the spread of such cancer frequently requires a colostomy during which the sphincter ani muscle is surgically excised. While the patient's bowel remains intact, there is no longer an associated sphincter muscle to hold the patient continent and control the movement of fecal material through the bowel. In such a case, the surgeon usually extends the patient's colon to a location outside the stomach. A mouth portion or stoma is formed at the external colon end and a bag is attached thereto to receive fecal material.
The corresponding arrangement of tubes and external valves which are needed to form the stoma end of the colon are often irritating to the patient. Moreover, externally worn bags are generally cumbersome in that they are subject to either changing or replacement, thereby increasing costs and/or subjecting the patient to a possible unsanitary environment. What is more, external belts, adhesives, and the like are typically required to secure the external bag to the body of the patient. Therefore, not only is the patient's mobility limited but the externally worn bag has been known to become separated from the patient. Moreover, the wearer of such externally worn bags sometimes requires assistance in attaching or removing the bag.
The best psychological and physiological treatment of a colostomy patient is to repair and artificially replace internal tissue so that the anal orifice terminates at its presurgery location. However, the artificial sphincter mechanisms heretofore available are not ideally suitable to reliably accomplish the foregoing.
Examples of conventional sphincteric mechanisms can be found be referring to one or more of the following U.S. patents: Nos.
3,863,622 Feb. 4, 1975 PA1 4,222,377 Sept. 16, 1980 PA1 4,386,601 June 7, 1983 PA1 4,417,567 Nov. 29, 1983 PA1 4,419,985 Dec. 13, 1983